Nutrition and Lifestyle in Bone Health
Developing and maintaining good bone health depends on a number of different factors. While we cannot control factors such as our gender or our family history, we can very easily make changes to our diet and lifestyle that will help to reduce our overall risk of developing severe osteoporosis in the future.Even though it is a solid structure, it is important to remember that bone is a living tissue, which is constantly breaking down and being renewed over our lifetime. Many of the processes involved in the manufacturing of new bone are affected by the food that we eat, which provides us with nutrients which can help build strong and healthy bones.
This section looks at the key vitamins and minerals in our diets which can help to strengthen our bones and help to protect against severe osteoporosis.
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Vitamin D
Vitamin D plays a vital role in bone health – without it, calcium which is required for strong and healthy bones cannot be absorbed.
Sunlight exposure is probably the most important source of vitamin D, and recent research suggests that we should expose the legs, arms, face and neck to natural sunlight for 10-15 minutes on at least 3 days per week during summer months (April to October) to satisfy requirements.
Diet can provide a key source of vitamin D for people who live at high latitudes (much of western Europe and the US ) and for those who are less well able to make their own vitamin D from sunlight. This includes the elderly and those with darkly pigmented skin living at Northerly latitudes. In these people, rich dietary sources of vitamin D should be emphasised. These would include oily fish, fish liver oil, liver itself, eggs, vitamin D enriched spreads, fortified milks and fortified breakfast cereals. However, typical dietary intakes for older adults are well below the recommended 10µg/day in a significant proportion of the population. Again, supplements should be considered where rich food sources of vitamin D are not regularly included in the diet.
Vitamin C is contained in highest amounts in citrus fruits and juices, peppers, tomatoes and tomato products, broccoli, green leafy vegetables and potatoes. It is involved in the formation and maintenance of bone, and may also be involved in the protection of bone tissue from damaging free radicals among smokers. High intakes of vitamin C have been associated with improved bone mass and reduced fracture rates, while low intakes have been associated with an accelerated loss of bone mineral density in later life. Five servings or more per day of fruit and vegetables, especially brightly coloured red, yellow, orange and green varieties, should meet requirements for most healthy adults.
Vitamin A is found in meat, liver, oily fish and fish oils, while its precursor Beta Carotene is found in plant sources including brightly coloured red, yellow, orange and green fruits and vegetables like peppers, bananas, tomatoes, oranges and green leafy vegetables. Too much animal-derived vitamin A (above 1500µg/day) has been associated with poor bone health and an increased risk of fracture. However, there is no evidence to suggest a negative effect on bone health, of high amounts of plant-derived vitamin A (Beta carotene). Furthermore, most people would very rarely consume in excess of 1500µg/day of vitamin A from animal sources under normal circumstances.
Vitamin K is produced primarily by the bacteria living in our gut, but you can also get it in the diet, mainly in dark green leafy vegetables, fruit and vegetable oils, but also to a lesser extent, in grains and dairy products. It is required for the formation of proteins present in the bone, and low vitamin K intakes have been associated with increased risk of fracture, presumably due to the weakening of bone tissue.
Calcium
Calcium is the most common mineral found in our bones and helps to give them strength and rigidity so it is an important factor in maintaining healthy bones. It is found in many foods, but the richest source of calcium is dairy produce including milk, cheese and yoghurt. While many people believe that there is less calcium in low fat dairy products, this is not the case. Low fat dairy products, particularly those which are fortified with additional vitamins and minerals, contain just as much calcium as their “full fat” alternatives.
Other sources of calcium include dark green leafy vegetables like cabbage, broccoli and especially spinach, fortified breakfast cereals, brown and white (but not wholemeal) bread and most fruit. However bear in mind that the calcium contained in these foods is generally not as easily absorbed as that found in dairy products.
When consuming calcium, avoid eating foods containing oxalates (rhubarb, almonds, cashews) and phytates (found in cereal grains, legumes and nuts) at the same time as they can inhibit the absorption of calcium.
The recommended daily intake of calcium is between 1,000mg and 1,200 mg per day. In practice, this means that most adults will get enough calcium by taking three to four portions of low fat dairy produce each day. Although to meet the extra demands of adolescence, pregnancy and lactation this may need to be increased to up to five portions per day. Research has also shown that increased calcium intake by women during the menopause and for the five years immediately following it, can significantly reduce the accelerated loss of bone mineral content which occurs at this time, helping to maintain bone strength.
Many people these days don't consume any dairy products at all, for a variety of reasons including popular diets and lactose intolerance. If you are not including any dairy produce in your diet, then it is very important to take a calcium supplement as well as incorporating other food sources which contain calcium, especially in adolescence. This is because most of our bone content is created during our teenage years and after our mid 30's, the rate of new bone manufactured in the body starts to decrease and more bone is lost than is formed. By maximising the amount of calcium deposited in our bones in early life, we can protect against osteoporosis and broken bones as this calcium is gradually leeched from the skeleton over later years. Indeed, supplementation with 1,000mg per day of calcium has been shown to improve the maximum bone mineral content achieved by adolescents with low dietary intakes.
Click here to view the calcium content of some common foods.
Phosphorous
Although phosphorous, like calcium, is a key mineral component of bone, there is little or no evidence that variations in the amount of phosphorous that you take in your diet has an effect on the strength of your bones. This may be because phosphorous is contained in a wide variety of foods including milk, poultry, meat, fish, eggs, grains, beans and pulses; so our requirements for this mineral will be met almost by default on a normal varied diet.
Very high phosphorous intakes (as seen in those with a very high consumption of fizzy drinks), in conjunction with low calcium intakes, have been suggested to have a negative effect on bone health, but the evidence for this is inconsistent.
Magnesium is a mineral found in fruit and vegetables, beans, peas, lentils, nuts, seeds, fish and dairy products. Because of this wide variety of sources, dietary magnesium deficiency is rare. It can occur in cases where a small dietary intake of magnesium coincides with regular high alcohol consumption. Intestinal malabsorption problems, such as coeliac or Crohn's disease, and the use of certain medications (diuretics or “water tablets”) can also increase the risk of magnesium deficiency.
High sodium intakes can result from adding salt to your food, eating too many processed foods (tinned foods, dried foods, biscuits, bread, etc.) or eating too many salty foods (crisps, cured meats etc.). These are all frequent features of the “western diet”, meaning that excessive sodium intakes are common. High sodium intakes have been shown to increase the loss of calcium in the urine, and where this occurs along with low calcium intake, this will cause calcium to be leeched from the bones. To prevent this, sodium intake from the sources above should be minimised, while ensuring you are getting a generous amount of potassium from fruit and vegetables (5 or more per day).
Potassium is found in greatest quantities in fruit and vegetables, but also in beans, peas, pulses and milk. An adequate intake of potassium is thought to reduce the loss of calcium in the urine, and an intake of 5 or more servings of fruit and vegetables per day has been recommended for improved bone health.
Very high fluoride intakes can adversely affect bone health, but this occurs very infrequently, except in areas with very high soil levels of fluoride.
While long-term protein deficiency could have a poor affect on bone health, this is very uncommon in industrialised societies. Diets high in meat are also thought to adversely affect bone health by increasing calcium excretion in the urine, but this has not been conclusively proven.
Excessive long term alcohol consumption, particularly in women, has been shown to be detrimental to bone health in several ways. These include decreased levels of bone-protective hormones like oestrogen and testosterone, poor dietary intakes of calcium and other nutrients, reduced bone formation and increased risk of fracture from falls. These negative effects provide further good reason to limit alcohol intake to no more than 2-3 units per day for women, and no more than 3-4 units per day for men, with several alcohol free days in between. The units of alcohol contained in some common drinks are illustrated below.
Beverage |
Volume |
Units |
Beer/Stout |
568mls (1 pint) |
2.3-2.4 |
Wine |
150mls (Medium glass) |
2.0 |
Spirits |
38mls (Irish pub measure) |
1.5 |
Alcopops |
330mls (Bottle) |
1.5-2.0 |
Table 2. Alcohol content of common beverages
Drinking too much coffee has been associated with poor bone health, but there is little evidence for this in people drinking less than eight standard cups of coffee per day. Care should be exercised with stronger percolated varieties of coffee.
Patients who suffer from anorexia nervosa are particularly susceptible to poor bone health for a number of reasons. They are mainly female, and will have a lower peak bone mass to begin with, but their very low food intake will result in a deficiency in several key nutrients including calcium, vitamin D, magnesium and protein. The extremely low energy intake and high activity levels characteristic of this condition, will result in depleted body fat stores and low oestrogen and testosterone levels, again removing the considerable protective effect of these hormones on bone.
This inability to digest lactose or milk sugar is characteristic of several ethnic groups including black Africans, Asians and Afro-Caribbeans. The abdominal discomfort experienced with milk and dairy consumption means that it is commonly associated with a low or absent intake of dairy products, resulting in a very low calcium intake. You can increase your calcium in these cases by using fermented milk products like yoghurts and cheeses, which have a minimal lactose content.
